1. Field of the Invention
The present invention relates to telecommunications systems, more particularly, to networks of mobile phone users sharing common contacts.
2. Description of the Related Art
In computer and telecommunications networks, presence information is a status indicator that conveys the ability and willingness of a potential communication partner to communicate.
The second most basic feature of a telephone (including cell phone, desktop phone, wireless phone, etc.)—after the ability to make telephone calls—is the address book. An address book is a database used for storing entries called contacts. Each contact entry usually consists of a few standard fields (for example: first name, last name, company name, address, telephone number, e-mail address, fax number, and mobile phone number). In this document the term, address book, refers to this database and the term, phone, to refer to any phone equipped with an address book having the ability to access the Internet.
The act of someone storing a contact in the address book of her phone is an implicit indication that she knows the entity (a person or a company) that the contact is describing. It is also an implicit indication that the users of two phones know each other if the address book of each phone contains the contact information of the other person.
A number of systems exist include a means by which users can voluntarily announce their presence on the system. Relevant presence information, which is also referred to herein as “presence”, is made available to those on the system that wish to receive the information.